I want to start playing around with the Starcraft 2 map editor.
I am looking to design maps for standard play. What are considered good qualities of a Starcraft 2 map? I am most interested in things like player start position, location of expansions, gold minerals, clifts, ramps, etc.
Balance is most important. Don't give someone a better start location than others.
This could include better choke points, better expansions, closer to rich mineral nodes.
Besides that, generally, modern maps have a main base, and a slightly less defendable expansion, but that's not necessarily required.
One other important but less tangible aspect of a map is race balance. Some types of maps seem to favor one race or another. A base with no ramp to wall off may hinder terran and protoss for example, while zerg normally don't wall in and so won't be affected.
You can't go wrong with symmetry. It doesn't have to be horizontal or vertical symmetry, specifically (see scrap station for an example exception), nor do doodads and terrain features need to be mirrored, but make sure that pathing, start locations, and resource distributions are as evenly symmetrical as possible.
